Multiple vulnerabilities in lighttpd

Published: 2016-08-01 | Updated: 2016-08-20

Risk	Medium
Patch available	YES
Number of vulnerabilities	3
CVE-ID	CVE-2016-5387
CWE-ID	CWE-79 CWE-61 CWE-284
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #3 is available.
Vulnerable software	lighttpd Server applications / Web servers
Vendor	lighttpd

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Cross-site scripting

EUVDB-ID: #VU339

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear]

CVE-ID: N/A

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The vulnerability can be used by a remote attacker to perform cross-site scripting attacks.

The vulnerability is caused by incorrect filtration of input data when displaying HTML and XML output. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in victim’s browser in security context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install the latest version 1.4.41.

Vulnerable software versions

lighttpd: 1.4.9 - 1.4.40

CPE2.3

External links

https://www.lighttpd.net/download/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Privilege escalation

EUVDB-ID: #VU338

Risk: Low

CVSSv4.0: 0.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: N/A

CWE-ID: CWE-61 - UNIX Symbolic Link (Symlink) Following

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to incorrect symlink handling in stat_cache, when “server.follow-symlink” is set to “disable”. A local attacker can overwrite arbitrary files on the target system with privileges of the web server.

Successful exploitation of this vulnerability may allow a local user to obtain elevated privileges.

Mitigation

Update to version 1.4.41.

Vulnerable software versions

lighttpd: 1.4.9 - 1.4.40

CPE2.3

External links

https://www.lighttpd.net/download/

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Httpoxy issue

EUVDB-ID: #VU337

Risk: Medium

CVSSv4.0: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2016-5387

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information and compromise vulnerable server.

The vulnerability exists due to a design error in multiple implementations of web servers. A remote unauthenticated attacker can use a specially crafted Proxy header in HTTP request to influence HTTP_PROXY environment variable and redirect application’s HTTP traffic to arbitrary proxy server.

Successful exploitation of this vulnerability may allow an attacker to gain unauthorized access to sensitive information and compromise vulnerable server.

This vulnerability is known as httppoxy.

Mitigation

Install the latest version 1.4.41.

Vulnerable software versions CPE2.3

External links

https://httpoxy.org/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.